Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Predators Have Outsized Influence Over Habitats

18.06.2012
Study of grasshoppers' diets shows that animals are an important part of organic matter decomposition

A grasshopper's change in diet to high-energy carbohydrates while being hunted by spiders may affect the way soil releases carbon dioxide into the atmosphere, according to research results published this week in the journal Science.


Grasshoppers' diets while being hunted may affect how soil releases carbon dioxide.

Grasshoppers like to munch on nitrogen-rich grass because it stimulates their growth and reproduction.

But when spiders enter the picture, grasshoppers cope with the stress from fear of predation by shifting to carbohydrate-rich plants, setting in motion dynamic changes to the ecosystem they inhabit, scientists have found.

"Under stressful conditions they go to different parts of the 'grocery store' and choose different foods, changing the makeup of the plant community," said Oswald Schmitz, a co-author of the paper and an ecologist at Yale University.

The high-energy, carbohydrate diet also tilts a grasshopper's body chemistry toward carbon at the expense of nitrogen.

So when a grasshopper dies, its carcass breaks down more slowly, thus depriving the soil of high-quality fertilizer and slowing the decomposition of uneaten plants.

"This study casts a new light on the importance of predation in natural communities," said Saran Twombly, program director in the National Science Foundation's Division of Environmental Biology, which funded the research.

"A clever suite of experiments shows that the dark hand of predation extends all the way from altering what prey eat to the nutrients their decomposing bodies contribute to soil."

Microbes in the soil require a lot of nitrogen to function and to produce the enzymes that break down organic matter.

"It only takes a slight change in the chemical composition of that animal biomass to fundamentally alter how much carbon dioxide the microbial pool is releasing to the atmosphere while it is decomposing plant organic matter," said Schmitz.

"This shows that animals could potentially have huge effects on the global carbon balance because they're changing the way microbes respire organic matter."

The researchers found that the rate at which the organic matter of leaves decomposed increased between 60 percent and 200 percent in stress-free conditions relative to stressed conditions, which they consider "huge."

"Climate and litter quality are considered the main controls on organic-matter decomposition, but we show that aboveground predators change how soil microbes break down organic matter," said Mark Bradford, a co-author of the study and also an ecologist at Yale.

Schmitz added: "What it means is that we're not paying enough attention to the control that animals have over what we view as a classically important process in ecosystem functioning."

The researchers took soil from the field, put it in test tubes and ground up grasshopper carcasses obtained from environments either with or without grasshopper predators.

They then sprinkled the powder atop the soil, where the microbes digested it.

When the grasshopper carcasses were completely decomposed, the researchers added leaf litter and measured the rate of leaf-litter decomposition.

The experiment was then replicated in the field at the Yale Myers Forest in northeastern Connecticut.

"It was a two-stage process where the grasshoppers were used to prime the soil, then we measured the consequences of that priming," said Schmitz.

The effect of animals on ecosystems is disproportionately larger than their biomass would suggest.

"Traditionally people thought that animals had no important role in recycling of organic matter, because their biomass is relatively small compared to the plant material that's entering ecosystems," Schmitz said.

"We need to pay more attention to the role of animals, however. In an era of biodiversity loss we're losing many top predators and larger herbivores from ecosystems."

Other co-authors are Michael Strickland of Yale, and Dror Hawlena of the Hebrew University of Jerusalem.

Media Contacts
Cheryl Dybas, NSF (703) 292-7734 cdybas@nsf.gov
Dave DeFusco, Yale University (203) 436-4842 david.defusco@yale.edu

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2012, its budget is $7.0 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives over 50,000 competitive requests for funding, and makes about 11,000 new funding awards. NSF also awards nearly $420 million in professional and service contracts yearly.

Cheryl Dybas | EurekAlert!
Further information:
http://www.nsf.gov

More articles from Life Sciences:

nachricht Antimicrobial substances identified in Komodo dragon blood
23.02.2017 | American Chemical Society

nachricht New Mechanisms of Gene Inactivation may prevent Aging and Cancer
23.02.2017 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>